Studs, threaded bolts or pins are commonly used in industrial applications to fasten equipment together or to fasten objects to some type of foundation. Over time, these studs can become frozen through the process of varying temperatures or exposure to elements. Threaded bolts can become frozen and have the heads twisted off in the removal process, leaving the user with a stud still frozen in place. Historically in all facets of industry extracting studs, bolts and pins has been a major time-consuming and financially-draining experience for maintenance managers around the world.
Oftentimes mechanics needing stud removal services will simply use vice grips or channel locks or the closest tool. One makeshift method commonly used is to “double nut” a stud by threading two nuts onto the stud to be removed, and tightening each nut against the other in opposite directions until they abut and fixedly lock onto the stud. The assembled double nut and stud combination is then removed from the required mechanical device using the double nuts as a “head” for a conventional wrench or socket tool. After the stud is removed, the nuts must be loosened by rotating each in opposite directions and then backed off from the removed stud. This cumbersome and time consuming method is eliminated by use of stud removal tools. A common problem resulting from the aforementioned methods, however, is that the studs will be removed with some damage to the housing, the studs, or both in most cases.
Common hand tools adapted for the purpose include pipe wrenches which employ opposing toothed jaws to bite into the stud when angularly displacing an elongated, radially extending handle to apply angular force to the stud. Other hand tools, chucks or grapples employ different numbers of such jaws, three being the most common, radially forced against the stud using cams, as illustrated by U.S. Pat. No. 3,371,562. A complication of stud removal using such tools is side loading, or the mechanical binding of threaded surfaces against each other. When side loading occurs, heat builds up due to friction between the threaded surfaces, creating a gall which is carried through the housing, tearing out the threads and impeding stud removal.
An alternative is the use of a stud removal tool. However, in the past many stud removal tools were complex, either requiring many individual pieces, or were of a design which required a considerable amount of effort and physical manipulation in removing the headless bolt from the associated mechanical device. Furthermore, traditional stud removal tools are heavy and, thus, cumbersome to use. Additionally, many of these tools were very expensive to manufacture because of the large number and intricacy of the individual components. Furthermore, many of the stud removal tools were designed in such a way that they were prone to breakage and rendered useless upon the failure of any single component.
For example, impact wrenches employing pneumatic pressure produce impulsed angular force to overcome frictional resistance to rotation of the stud. Sockets for use with impact wrenches commonly rely upon differential rotation between the socket and a vehicle bearing gripping jaws and carried within an axially aligned cavity in the socket. Cams on the cavity walls mate with outer curved surfaces of the jaws as the socket rotates to bias the jaws radially inward and into frictional contact with the outer perimeter of the stud. Teeth borne on the inner surface of the jaws bite into the stud to enhance the gripping effect of the frictional contact.
One type of device accomplishes removal by cutting the stud out of the fixture using a blow torch. However, this method of stud removal results in damage to the stud and the fixture. One solution is to use devices that either drill the stud, or cut into the stud, so that torque can be applied to the nut for removal. However, these devices also result in further stripping of the threads of the stud, impeding removal from the fixture.
Another type of device accomplishes fastener removal by inserting an electrode into the broken stud and using a series of intermittent electrical arcs to disintegrate the stud, leaving a stud casing which is then removed manually. Finally the threads of the fixture are cleaned. However, this method of removal results in damage to the stud, is time consuming, involves multiple steps for stud removal, and may result in damage to the fixture.
Other devices using an air impact tool for the removal of large studs exist. Such devices may require a cartridge having many small parts that is used to apply torque to the damaged stud. These multiple small parts of the cartridge, such as multiple helical springs, studs and screws holding gripping jaws together, are prone to breakage when the rotative force of an air impact tool is applied.
Another prior art stud removal tool consists of a housing having a cylindrical bore with finger splits on one end of the housing, and the other end of the housing connecting to an air impact tool. However, the finger splits of the housing cannot fit over multiple stud sizes, so that the tool is limited in usage. A further complication of the cartridges and associated parts is the use of a retaining ring or clip. The retaining ring or clip is prone to breakage, resulting in a damaged and useless tool.
Yet another complication is “chattering.” where the tool does not perfectly conform to the size of the fastener. When rotative force is applied using an air impact tool, the removing tool “chatters” over the damaged corners of the fastener, further stripping the fastener or damaging the tool interface with the fastener, and causing ‘radii’ to form on the end of the tool.
The use of a set of tools having a multiplicity of sizes to conform to different stud sizes exists which proposes to solve the problem of imperfect conformance between removal tool and stud size. However, regardless of the size, the prior art nonetheless results in chattering from an imperfect size conformance; thus, stripping of the thread occurs.
Further, the use of a set of tools having a multiplicity of sizes to conform to stud size presents another complication. If there exists a multiplicity of removal tool sizes in a set, the loss of one of the tools results in a useless tool set.
Furthermore, the insertion of studs is often a difficult, tedious and very expensive task. One makeshift method commonly used is to “double nut” a stud by threading two nuts onto the stud to be inserted, and tightening each nut against the other in opposite directions until they abut and fixedly lock onto the stud. The assembled double nut and stud combination then is inserted into the required mechanical device using the double nuts as a means for driving the assembled combination. After the stud is mounted, the nuts must be loosened by rotating each in opposite directions and then backed off from the mounted stud. This cumbersome and time consuming method is eliminated by forms of stud insertion tools.
However, in the past many stud driving and insertion tools were complex, either requiring many individual pieces, or were of a design which required considerable amount of effort and physical manipulation in mounting the headless bolt or stud into the associated mechanical device. Many of these tools were very expensive to manufacture because of the large number and intricacy of the individual components.